Implement browser testing framework into the pipeline

[daine]

📇 User story

As a developer, I want to have end to end testing, so that I am confident in deploying my code changes

✅ Definition of Done

• [x] Build spec in amplify.tf is updated to contain a test phase
• [x] Production build spec is updated
• [x] Staging build spec is updated

📜 Acceptance criteria

• [x] One simple test is running successfully
• [x] #443

📝 More info

Cypress + Amplify

[daine]

Grooming notes: #316